Honeywell Q674L - Manual (Page 7)

69-0392—9 7
T874R THERMOSTATS AND Q674L SUBBASES
Fig. 11. Internal schematic and typical wiring diagram for Y594R1672 (T874R1889/Q674L1736) and Y594R1698
(T874R1905/Q674L1777). Exact replacement for York model nos. 2TH11702324 and 6TH11702224.
H2
FALL
H1
FALL
C1
L1
(HOT)
L2
1
FAN SWITCH
AUTO
ON
FAN RELAY
AUX. HT. RELAY
"H" RELAY
EM. HT. RELAY
CHANGEOVER VALVE (COOL)
COMPRESSOR
CONTACTOR
C815A1039
THERMISTOR
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
EM. HT.
LED (RED)
G
R
W
H
B
X
T
O
Y
12
11
6
5
4
3
2
H1/C1
ANTICIPATOR
H2
ANTICIPATOR
RESET HEATER
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M3173A
THERMOSTAT SUBBASE SYSTEM COMPONENTS
1
L1
(HOT)
L2
1
X
L
W2
EM. HT.
LED (RED)
AUX. HT.
LED (GRN) AUX. HT.
RELAY
FAN RELAY
"B" RELAY
G
COOL CHANGEOVER
VALVE
EM. HT. RELAY
COMPRESSOR
CONTACTOR
O
Y
E
B
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
H1/C1
ANTICIPATOR
C1
H1
FALL
H2
W3
AUX. HT.
RELAY
H2
ANTICIPATOR
1
2
3
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
TERMINAL LABELED C/X ON SOME MODELS.
W3 TERMINAL AVAILABLE ON SOME MODELS ONLY.
M3683A
AUTO
ON
FAN
SWITCH
FALL
R
2
3
4
6
THERMOSTAT SUBBASE SYSTEM COMPONENTS
Fig. 12. Internal schematic and typical wiring diagram for Y594R1797 (T874R1988/Q674L1868).